Asafa Powell steps up his bid for Usain Bolt's crown

Asafa Powell has warned Usain Bolt he will only get quicker after clocking the fastest time of the year for the 100metres in Lausanne.

Powell won the highlight of the Diamond League meeting in 9.78sec to mark himself out as a serious contender to his fellow Jamaican's World Championship crown in Daegu at the end of August.

"Anything below 9.8 is really good. It's only the second race of the season so things can only get better as the season progresses," he said. "I can't wait to face Usain."

British 400m hurdler Dai Greene also marked himself out as a serious World Championship medallist with victory over a star-studded field which included 2004 Olympic champion Felix Sanchez and world champion Kerron Clement.

But Phillips Idowu was upstaged in the triple jump by Frenchman Teddy Tamgho, whose leap of 17.91m put him well clear of the Briton's best effort of 17.52m.